Treatment of a tooth

ABSTRACT

An apparatus and method is disclosed for treating a tooth with an active agent such as a tooth whitening agent comprising a stint having an internal region defined by an internal surface. A plurality of indentations are formed in the internal surface for retaining the active agent to maintain the active agent in contact with the tooth when the stint is applied upon the tooth. The stint is molded from a sheet of plastic material with the indentations being formed by an abrading process such as abrasive blasting or the like.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of application Ser. No. 08/009,355 filed Jan. 26,1993, and now U.S. Pat. No. 5,356,291, which is a continuation ofapplication Ser. No. 793,244 filed Nov. 12, 1991 and now abandoned,which is a continuation of application Ser. No. 612,599 filed Nov. 5,1990 and now abandoned, which is a continuation-in-part of applicationSer. No. 374,985 filed Jul. 3, 1989 and now U.S. Pat. No. 4,968,251. Theentire disclosures of each of the aforementioned patents andapplications are hereby incorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field Of The Invention

This invention relates to medicine and dentistry and more particularlyto an improved method and apparatus for applying an active agent to thesurface of a tooth and/or other oral structures.

2. Prior Art Statement

The prior art has known many devices and methods for externally treatinga tooth or teeth of a patient. The most primitive method of externallytreating a tooth involves the direct application of an active agent tothe tooth of the patient. Examples of the external treatment of a toothincludes the direct application of active agents such as fluoride, toothwhiteners, antibiotics, antihistamines and topical anesthetics.

Although the external treatment of a tooth by the direct application ofan active agent has achieved some success, several problems exist withthis method. First, the direct application of an active agent isgenerally inefficient since the active agent can be applied to thesurface of the tooth for only a relatively short period of time. Therelatively short period of time of application is determined by thelength of time the active agent remains on the tooth of the patient. Thelength of time the active agent remains on the tooth of the patient isgenerally determined by the viscosity of the active agent and theability of the active agent to remain on the tooth as well as theability of the patient to remain immobile during the treatment.

In an effort to overcome these problems, some in the prior art haveincreased the concentration of the active agent in an effort to producesatisfactory results within the limited period of time permitted by thedirect application of the active agent. Unfortunately, the increase inthe concentration of the active agent produces undesirable side effectsfor the patient.

Others in the prior art have utilized a plastic stint molded to overlaythe teeth of the patient in an effort to retain a tooth whitening agentin contact with the teeth of a patient over an extended period of time.Such a method is set forth in an article entitled "Nightguard VitalBleaching" which has been published in Ouintessence International,Volume 20, March, 1989. In this method a stint is molded to fit theentire upper or lower teeth of the patient and to seal with the gingivaof the patient. The active agent is introduced into the stint, and thestint is inserted upon the teeth of the patient to retain the activeagent in intimate contact with the teeth of the patient.

Although the use of a plastic stint allowed the active agent to remainin contact with the tooth for an extended period of time, the use of theplastic stint had certain disadvantages. First, since the plastic stintwas molded to intimately fit with the entire upper or lower teeth of thepatient, the stint was uncomfortable due to the tightness of the fitwith the teeth. Second, the stint sealed with the gingiva of the patientmaking the stint incapable of fitting with a single tooth or pluralteeth, since such a stint could not properly seal with the gingiva ofthe patient. Third, the stint had to be cut back adjacent to thegingival margin to prevent undesired deterioration of the gingiva due tothe intimate contact of the stint with the gingiva during the treatmentprocess. Fourth, intimate fit of the stint with the entire upper orlower teeth of the patient prevented ingress and egress of oxygen to theinternal region of the stint. Fifth, intimate fit of the stint with theentire upper or lower teeth of the patient made the stint difficult toremove in some instances. Sixth, notwithstanding the intimate fit of thestint with the entire upper or lower teeth of the patient, the activeagent within the internal region of the stint would over time migratefrom the stint thus reducing the effectiveness of the active agent uponthe teeth.

In my prior application Ser. No. 374,985 filed Jul. 3, 1989 now U.S.Pat. No. 4,968,251, a retaining material was interposed between thestint and the tooth. The retaining material acted as a reservoir andmaintained the active agent in intimate contact with the tooth for alonger period of time than the whitening processes of the prior art.Furthermore, the retaining material could provide a preferentialtreatment of a selected portion of a tooth.

It is an object of the present invention to provide an improved methodand apparatus for treating a tooth with an active agent which producesresults which are superior to the results heretofore known to the art.

Another object of this invention is to provide an improved method andapparatus for treating a tooth with an active agent which is analternate apparatus and method to my prior application Ser. No. 374,985filed Jul. 3, 1989 now U.S. Pat. No. 4,968,251.

Another object of this invention is to provide an improved method andapparatus for treating a tooth with an active agent wherein a retainingmeans is disposed within the stint for maintaining the active agentagainst the surface of the tooth of the patient.

Another object of this invention is to provide an improved method andapparatus for treating a tooth with an active agent wherein a pluralityof indentations are formed on an inner surface of the stint forproviding baffles for the active agent to prevent the loss of the activeagent from the stint.

Another object of this invention is to provide an improved method andapparatus for treating a tooth or other oral structures within the oralcavity with an active agent.

Another object of this invention is to provide an improved method andapparatus for treating a tooth with an active agent which is capable offitting with a single tooth or a plurality of teeth of the patient.

Another object of this invention is to provide an improved method andapparatus for treating a tooth with an active agent wherein the stintmay overlie the gingival margin without deterioration or irritation ofthe gingiva of the patient.

Another object of this invention is to provide an improved method andapparatus for treating a tooth with an active agent wherein the stintallows the ingress and egress of oxygen to the gingival tissue adjacentto the stint.

Another object of this invention is to provide an improved method andapparatus for treating a tooth with an active agent wherein the stintmay be easily removed by the patient.

The foregoing has outlined some of the more pertinent objects of thepresent invention. These objects should be construed as being merelyillustrative of some of the more prominent features and applications ofthe invention. Many other beneficial results can be obtained by applyingthe disclosed invention in a different manner or modifying the inventionwithin the scope of the invention. Accordingly other objects and a fullunderstanding of the invention may be had by referring to the summary ofthe invention, the detailed description describing the preferredembodiment, in addition to the scope of the invention defined by theclaims taken in conjunction with the accompanying drawings.

SUMMARY OF THE INVENTION

The present invention is defined by the appended claims with specificembodiments being shown in the attached drawings. For the purpose ofsummarizing the invention, the invention relates to an improved methodof treating a tooth with an active agent, comprising the steps of makinga model of the tooth and molding a stint to define an internal region tooverlay the tooth. Indentations are formed within the internal region ofthe stint. The active agent is introduced into the stint prior to thestint being applied upon the tooth. The indentations maintain the activeagent in contact with the tooth and provide a reservoir for excessquantities of the active agent.

In a more specific embodiment of the invention, the stint is vacuumformed from a sheet of plastic material over the model of the tooth or aplurality of teeth. The stint is trimmed to terminate at the juncture ofthe tooth and the gingiva tissue. The indentations are formed within theinternal region of the stint by abrading an internal surface of thestint. Preferably, the indentations are formed by an abrasive blastingprocess after the completion of the molding of the stint. The stintseals the internal region from the external region of the stintproximate the termination of the stint at the juncture of the tooth andthe gingiva tissue.

In one embodiment of the invention, the indentations are preferentiallyformed into selected portions of the internal surface of the stint topreferentially treat a portion of the tooth adjacent the indentations.

The foregoing has outlined rather broadly the more pertinent andimportant features of the present invention in order that the detaileddescription that follows may be better understood so that the presentcontribution to the art can be more fully appreciated. Additionalfeatures of the invention which form the subject of the claims of theinvention will be described hereinafter. It should be appreciated bythose skilled in the art that the conception and the specificembodiments disclosed may be readily utilized as a basis for modifyingor designing other structures for carrying out the same purposes of thepresent invention. It should also be realized by those skilled in theart that such equivalent constructions do not depart from the spirit andscope of the invention as set forth in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the nature and objects of the invention,reference should be made to the following detailed description taken inconnection with the accompanying drawings in which:

FIGS. 1A-1F are rear views partially in section of the prior art processof treating a tooth with a stint with FIGS. 1A-1F illustrating theindividual process steps;

FIG. 1A is a first step in the prior art process illustrating thepositioning of a model of the teeth upon a vacuum table;

FIG. 1B is a second step in the prior art process illustrating theheating of a plastic material for forming the stint;

FIG. 1C is a third step in the prior art process illustrating thepositioning of the heated plastic material upon the model;

FIG. 1D is a fourth step in the prior art process illustrating thevacuum forming of the heated plastic material upon the model to form thestint;

FIG. 1E is a fifth step in the prior art process illustrating theremoval of the vacuum formed stint from the model and the trimming ofthe vacuum formed stint;

FIG. 1F is a seventh step in the prior art process illustrating theintroduction of the active agent within the stint;

FIGS. 2A-2F are rear views partially in section of a first embodiment ofthe present invention for treating a tooth with a stint with FIGS. 2A-2Fillustrating the individual process steps;

FIG. 2A is a first step in the first embodiment of the present inventionillustrating the positioning of a model of the teeth upon a vacuumtable;

FIG. 2B is a second step in the first embodiment of the presentinvention illustrating a sheet of a retaining material positioned uponthe model of the teeth and the heating of a plastic material for formingthe stint;

FIG. 2C is a third step in the first embodiment of the present inventionillustrating the positioning of the heated plastic material upon themodel with the retaining material interposed therebetween;

FIG. 2D is a fourth step in the first embodiment of the presentinvention illustrating the vacuum forming of the heated plastic materialand the retaining material upon the model to form the stint;

FIG. 2E is a fifth step in the first embodiment of the present inventionillustrating the removal of the vacuum formed stint from the model andthe trimming of the vacuum formed stint and the retaining material;

FIG. 2F is a sixth step in the first embodiment of the present inventionillustrating the introduction of the active agent within the retainingmaterial within the stint;

FIG. 3A-3H are rear views partially in section of a second embodiment ofthe present invention for treating a tooth with a stint with FIGS. 3A-3Hillustrating the individual process steps;

FIG. 3A is a first step in the second embodiment of the presentinvention illustrating the positioning of a model of the teeth upon avacuum table;

FIG. 3B is a second step in the second embodiment of the presentinvention illustrating the heating of a plastic material for forming thestint;

FIG. 3C is a third step in the second embodiment of the presentinvention illustrating the positioning of the heated plastic materialupon the model;

FIG. 3D is a fourth step in the second embodiment of the presentinvention illustrating the vacuum forming of the heated plastic materialupon the model to form the stint;

FIG. 3E is a fifth step in the second embodiment of the presentinvention illustrating the removal of the vacuum formed stint from themodel and the trimming of the vacuum formed stint;

FIG. 3F is a sixth step in the second embodiment of the presentinvention illustrating the positioning of a retaining material upon themodel;

FIG. 3G is a seventh step in the second embodiment of the presentinvention illustrating the forming of the retaining material upon themodel by the formed stint;

FIG. 3H is an eighth step in the second embodiment of the presentinvention illustrating the trimming of the retaining material to thestint;

FIG. 3I is a ninth step in the second embodiment of the presentinvention illustrating the introduction of the active agent within theretaining material within the stint;

FIG. 4 is a sectional view of the improved stint shown in FIGS. 2A-2Fdisposed upon a tooth of a patient;

FIG. 5 is an enlarged sectional view of the improved stint shown inFIGS. 2A-2F disposed upon a tooth of a patient;

FIG. 6 is a sectional view of the improved stint shown in FIGS. 3A-3Idisposed upon a tooth of a patient;

FIG. 7 is a sectional view of the improved stint shown in FIGS. 3A-3Idisposed upon a tooth of a patient with the retaining material beingpreferentially inserted into a selected portion of the stint topreferentially treat a selected portion of the tooth;

FIGS. 8A-8H are rear views partially in section of a third embodiment ofthe present invention illustrating the process of treating a tooth witha stint with FIGS. 8A-8H illustrating the individual process steps;

FIG. 8A is a first step in the third embodiment of the present inventionillustrating the positioning of a model of the teeth upon a vacuumtable;

FIG. 8B is a second step in the third embodiment of the presentinvention illustrating the heating of a plastic material for forming thestint;

FIG. 8C is a third step in the third embodiment of the present inventionillustrating the positioning of the heated plastic material upon themodel;

FIG. 8D is a fourth step in the third embodiment of the presentinvention illustrating the vacuum forming of the heated plastic materialupon the model to form the stint;

FIG. 8E is a fifth step in the third embodiment of the present inventionillustrating the removal of the vacuum formed stint from the model andthe trimming of the vacuum formed stint;

FIG. 8F is a sixth step in the third embodiment of the present inventionillustrating the abrading of an internal region of the stint;

FIG. 8G is a seventh step in the third embodiment of the presentinvention illustrating the cleaning of an internal region of the stint;

FIG. 8H is an eighth step in the third embodiment of the presentinvention illustrating the introduction of the active agent within thestint;

FIG. 9 is a sectional view of the improved stint shown in FIG. 8Hdisposed upon a tooth of a patient;

FIG. 10 is an enlarged view of a portion of FIG. 9.

Similar reference characters refer to similar parts throughout theseveral Figures of the drawings.

DETAILED DISCUSSION

FIGS. 1A-1F illustrate a method of whitening a tooth with an activeagent in accordance with the teaching of the prior art such as the priorart article "Nightguard Vital Bleaching" (Quintessence International,Volume 20, March, 1989). FIG. 1A is a first step in the prior artprocess illustrating the positioning of a model 10 upon an upper surface12 of a vacuum table 14. The vacuum table 14 defines a plurality ofapertures 16 which are connected by conduits 18 to a manifold 20. Themanifold 20 is connected to a source of vacuum (not shown). A model 10is a reproduction of the teeth 22 of a patient and is constructed in aconventional manner as should be well known to those skilled in the art.The model 10 is positioned upon the upper surface 12 of the vacuum table14 as shown.

FIG. 1B is a second step in the prior art process illustrating theheating of a sheet plastic material 24 for forming a stint 30.

FIG. 1C is a third step in the prior art process illustrating thepositioning of the heated sheet of plastic material 24 upon the model10. The heated sheet of plastic material 24 begins to form into thecontour of the model 10 by the action of gravity.

FIG. 1D is a fourth step in the prior art process illustrating theapplication of a vacuum to the manifold 20 for vacuum forming of theheated plastic material 24 upon the model 10 to form the stint 30. Thevacuum forming process forms the heated plastic material 24 into anexact reproduction of the outer surfaces of the teeth 22 of the patient.

FIG. 1E is a fifth step in the prior art process illustrating theremoval of the stint 30 from the model 10. The stint 30 is formed withan internal region 31 and an external region 32. The stint 30 is trimmedby a cutting tool (not shown) such as crown scissors to terminate at 34proximate the junction 36 of the teeth 22 and the gingival tissue 38commonly referred to as the tooth gingival margin.

FIG. 1F is a seventh step in the prior art process illustrating theintroduction of the active agent 40 within the internal region 31 of thestint 30. The prior art has used this process for whitening teeththrough the use of a nonaqueous oral peroxy compound as an active agent.After the active agent is applied, the stint 30 containing the activeagent 40 is applied upon the teeth 22 of the patient. The termination 34of the stint 30 seals with the gingiva 38 to retain the active agent 40within the internal region 31 of the stint 30.

FIGS. 2A-2F are rear views partially in section of a first embodiment ofthe present invention for treating a tooth with a stint and with FIGS.2A-2F illustrating the individual process steps. FIG. 2A is a first stepin the first embodiment of the present invention illustrating thepositioning of a model 110 upon an upper surface 112 of a vacuum table114. The vacuum table 114 defines a plurality of apertures 116 which areconnected by conduits 118 to a manifold 120 for connection to a sourceof vacuum (not shown). A model 110 is a reproduction of the teeth 122 ofa patient and is constructed in a conventional manner. The model 110 ispositioned upon the upper surface 112 of the vacuum table 114 as shown.

In contrast to the prior art process shown in FIGS. 1A-1F, a retainingmaterial 126 is positioned upon the model 110. The retaining material inthis embodiment is shown as a close cell foam material such as lowdensity foamed polyethylene having a thickness of 1/32" to 3/32". Theretaining material 126 possesses a natural resiliency as well as nonuniform outer surfaces which are desirable for the practice of thepresent invention.

FIG. 2B is a second step in the first embodiment of the presentinvention illustrating the heating of a plastic material 124 for formingthe stint 130. The plastic material 124 for the stint 130 is againselected to be easily formed at moderate temperatures such as 0.020 inchthickness polycarbonate. Preferably, the melting temperature of theretaining material 126 is less than the melting temperature of theplastic material 124 for the stint 130.

FIG. 2C is a third step in the first embodiment of the present inventionillustrating the positioning of the heated sheet of plastic material 124upon an inner surface 126A of the retaining material 126 while theretaining material 126 rests on the model 110. Since the meltingtemperature of the retaining material 126 is less than the meltingtemperature of the stint plastic material 124, the inner surface 126A ofthe retaining material 126 is heat fused to the plastic material 124.

Preferably, the melting temperature of the plastic material 124 for thestint 130 is selected to be higher than the melting temperature of theretaining material 126 to enable heat fusion of the inner surface 126Awhile being sufficiently low to prevent the destruction, melting ordistortion of the interior or an outer surface 126B of the retainingmaterial 126. Furthermore, only the inner surface 126A of the retainingmaterial 126 is heat fused to the plastic material 124 for maintainingthe resiliency of the resilient material 126.

After the heated sheet of plastic material 124 fuses with the retainingmaterial 126, the sheet of plastic material 124 and the fused retainingmaterial 126 begin to form into the contour of the model 110 by theaction of gravity.

FIG. 2D is a fourth step in the first embodiment of the presentinvention illustrating the application of a vacuum to the manifold 120for vacuum forming of the heated plastic material 124 and the interposedretaining material 126 upon the model 110 to form the stint 130. Thevacuum forming process forms the heated plastic material 124 into areproduction of the outer surfaces of the teeth 122 of the patient.However, in contrast to the prior art process, the internal region ofthe stint 130 is spaced from the outer surfaces of the teeth 122 of thepatient by the thickness of the retaining material 126.

FIG. 2E is a fifth step in the first embodiment of the present inventionillustrating the removal of the stint 130 from the model 110. The stint130 is formed with an internal region 131 now defined by the retainingmaterial 126 and an external region 132. The stint 130 is trimmed by acutting tool (not shown) to terminate at 134 proximate the junction 136of the teeth 122 and the gingiva tissue 138. As the stint 130 istrimmed, both the plastic material 124 and the retaining material 126are simultaneously trimmed by the cutting tool.

FIG. 2F is a sixth step in the first embodiment of the present inventionillustrating the introduction of the active agent 140 within theinternal region 131 of the stint 130. The presence of the retainingmaterial 126 in the internal region 131 of the stint 130 aids inretaining the active agent 140 within the stint 130 and in closeproximity to the teeth 122 of the patient to provide superior resultsrelative to the prior art.

After the active agent 140 is introduced into the internal region 131 ofthe stint 130, the stint 130 is inserted over the teeth 122 of thepatient. The non uniform surface of the retaining material 126 withinthe stint 130 provides baffles to retain the active agent 140 within theinternal region 131 of the stint 130.

FIG. 3A-3I are rear views partially in section of a second embodiment ofthe present invention for treating a tooth with a stint with FIGS. 3A-3Iillustrating the individual process steps. FIG. 3A is a first step inthe second embodiment of the present invention illustrating thepositioning of a model 210 of the teeth 222 of a patient upon an uppersurface 212 of a vacuum table 214 with the vacuum table 214 defining aplurality of apertures 216 which are connected by conduits 218 to amanifold 220 for connection to a source of vacuum (not shown).

FIG. 3B is a second step in the second embodiment of the presentinvention illustrating the heating of a plastic material 224 for forminga stint 230. The plastic material 224 is again selected to be easilyformed at moderate temperatures by conventional means.

FIG. 3C is a third step in the second embodiment of the presentinvention illustrating the positioning of the heated plastic material224 upon the model 210 with the heated sheet of plastic material 224beginning to form into the contour of the model 210 by the action ofgravity.

FIG. 3D is a fourth step in the second embodiment of the presentinvention illustrating the application of a vacuum to the manifold 220for vacuum forming of the heated plastic material 224 upon the model 210to form the stint 230.

FIG. 3E is a fifth step in the second embodiment of the presentinvention illustrating the removal of the stint 230 from the model 210with the stint 230 being formed with an internal region 231 and anexternal region 232. The stint 230 is trimmed by a cutting tool (notshown) to terminate at 234 proximate the junction 236 of the teeth 222and the gingival tissue 238 commonly referred to as the tooth gingivalmargin.

FIG. 3F is a sixth step in the second embodiment of the presentinvention illustrating the positioning of a retaining material 226 uponthe model 210. In this embodiment, the retaining material 226 is shownas a thin sheet of fibrous absorbent retaining material. Preferably, thefibrous absorbent retaining material 226 has a thickness of 0.001" to0.005". The retaining material 226 may be optionally moistened forfacilitating the formation thereof as will be described hereinafter.

FIG. 3G is a seventh step in the second embodiment of the presentinvention illustrating the forming of the retaining material 226 uponthe model 210 by the stint 230. The formed stint 230 is placed upon themodel 210 with the retaining material 226 interposed therebetween. Theformed stint 230 and the model 210 form the retaining material into theshape of the internal region 231. The retaining material 226 isfrictionally retained within the internal region 231 of the stint 230.If desired, an adhesive may be applied to the stint 230 and/or theretaining material 226 prior to placing the stint 230 upon the model 210with the retaining material 226 interposed therebetween for permanentlysecuring the retaining material 226 to the stint 230.

FIG. 3H is an eighth step in the second embodiment of the presentinvention illustrating the trimming of the retaining material 226 to thestint 230. The retaining material 226 is trimmed by a cutting tool (notshown) adjacent the termination 234 of the stint 230.

FIG. 3I is a ninth step in the second embodiment of the presentinvention illustrating the introduction of the active agent 240 withinthe internal region 231 of the stint 230. The presence of the absorbentretaining material 226 in the internal region 231 of the stint 230allows the active agent 240 to be absorbed within the retaining material226 to retain the active agent 240 in close proximity to the teeth 222of the patient to provide superior results relative to the prior art.

FIG. 4 is an enlarged sectional view of the first embodiment of theimproved stint 130 shown in FIGS. 2A-2F containing the active agent 140disposed upon a tooth 122 of the patient. The termination 134 of thestint 130 approximates the gingiva 138 to retain the active agent 140within the internal region 131 of the stint 130.

In the first embodiment shown in FIG. 4, the retaining material 126 notonly aids in the retention of the active agent but also allows theingress and egress of oxygen to the gingiva tissue 138. Accordingly, thestint 130 of the present invention may utilize an overlap 144 of thegingiva tissue 138 by as much as 3.0 millimeters. The overlap 144 of thegingiva tissue 138 allowed by the stint 130 of the present inventionprovides a superior adaptation for treatment of the gingival tissue overthe prior art stint 30.

The presence of the retaining material 126 and the natural resiliency ofthe closed cell foam makes the stint 130 more comfortable to wear forthe patient. Accordingly, the patient will be inclined to wear the stint130 of the present invention for a longer period of time relative to theprior art stint 30 thus producing faster results relative to the priorart stint 30. Additionally, the non uniform surface of the closed cellfoam enhances the retention of the active agent within the stint 130.

FIG. 5 is an enlarged sectional view of a portion of the improved stint130 shown in FIG. 4. The foam retaining material 126 has a plurality ofbaffles or indentations 146 to trap and hold the active agent 140against the tooth 122 to provide a superior performance relative to theprior art. Although the prior art stint 30 was closely fitted to thesurface of the teeth 22, the active agent 40 within the stint 30 tendedto wash out of the stint 30. In addition, areas where the prior artstint closely fitted against the surface of the tooth prevented theactive agent from treating that portion of the tooth. This disadvantageof the prior art stint caused undesired irregular treatment of thetooth.

In the first embodiment of the invention, the plurality of baffles 146of the retaining material 126, retains the active agent 140 within thestint 130 and impedes the washing away of the active agent 140 from thestint 130. Accordingly, the active agent 140 stays in contact with thesurface of the teeth 122 of the patient thus providing superior resultswith the same active agent 140. Furthermore, the baffles 146 maintainthe active agent uniformly against the surface of the tooth to provide auniform treatment.

FIG. 6 is an enlarged sectional view of the second embodiment of theimproved stint 230 shown in FIGS. 3A-3I disposed upon a tooth 222 of apatient. The termination 234 of the stint 230 ends with the gingiva 238to retain the active agent 240 within the internal region 231 of thestint 230. In this example, the retaining material 226 is uniformlydisposed about the entire external surface of the tooth 222 of thepatient.

FIG. 7 is an enlarged sectional view of the second embodiment of theimproved stint 230 shown in FIGS. 3A-3I disposed upon a tooth 222 of apatient with the retaining material 226 being preferentially insertedinto a selected portion of the stint 230 to preferentially treat aselected portion of the tooth 222. In some instances, only a portion ofthe tooth 222 requires the treatment by the active agent 240.Accordingly, the retaining material 226 may be preferentially insertedinto a selected portion of the stint 230. For example, the selectedportion of the tooth 222 is first identified and the retaining material226 is temporarily affixed by means such as a temporary adhesive to themodel 210 to cover the selected portion of the tooth 222. Thereafter,the stint 230 is molded in the manner shown in FIGS. 3A-3E. Theretaining material 226 may then be removed from the model 210 and may beaffixed by means such as a permanent adhesive to the selected portion ofthe stint 230. When the active agent is applied to the retainingmaterial 126 in the selected portion of the stint 230, the retainingmaterial 126 is in register with the selected portion of the stint 230for preferentially treating the selected portion of the tooth 222. Thisadvantage of the second embodiment of the improved stint enables theselective treatment of a single tooth or a selected portion or portionsof a single tooth or a plurality of selected teeth.

FIGS. 8A-8H are rear views partially in section of a third embodiment ofthe present invention illustrating the process of treating a tooth witha stint.

FIG. 8A is a first step in the third embodiment of the present inventionillustrating the positioning of a model 310 upon an upper surface 312 ofa vacuum table 314 having a plurality of apertures 316 which areconnected by conduits 318 to a manifold 320.

FIG. 8B is a second step in the third embodiment of the presentinvention illustrating the heating of a plastic material 324 for formingthe stint 330.

FIG. 8C is a third step in the third embodiment of the present inventionillustrating the positioning of the heated plastic material 324 upon themodel 310. The heated sheet of plastic material 324 begins to form intothe contour of the model 310 by the action of gravity.

FIG. 8D is a fourth step in the third embodiment of the presentinvention illustrating the application of a vacuum to the manifold 320for vacuum forming of the heated plastic material 324 upon the model 310to form the stint 330. The vacuum forming process forms the heatedplastic material 324 into an exact reproduction of the outer surfaces ofthe teeth 322 of the patient.

FIG. 8E is a fifth step in the third embodiment of the present inventionillustrating the removal of the vacuum formed stint 330 from the model310. The stint 330 is formed with an internal region 331 defined by aninternal surface 331A and an external region 332. The stint 330 istrimmed by a cutting tool (not shown) such as crown scissors toterminate at 334 proximate the junction 336 of the teeth 322 and thegingival tissue 338 commonly referred to as the tooth gingival margin.

FIG. 8F is a sixth step in the third embodiment of the present inventionillustrating the abrading of the internal surface 331A of the internalregion 331 of the stint 310. Preferably, the abrading of the internalsurface 331A is accomplished by projecting an abrasive 360 onto theinternal surface 331A of the stint 330 after the completion of themolding of the stint 330. In this embodiment, the abrasive 360 isprojected from a nozzle 362 connected by a hose 364 to an abrasiveblaster 366. The abrasive blaster 366 projects the abrasive 360 at ahigh velocity from the nozzle 362 onto the internal surface 331A of thestint 330 to create the indentations 346 thereby. Although many types ofabrasive may be used with this process, a high quality sand product issuitable for use with the present invention.

FIG. 8G is a seventh step in the third embodiment of the presentinvention illustrating the cleaning of an internal region 331 of thestint 330 to remove any remaining abrasive 360. In this embodiment, thestint 330 is immersed in an ultrasonic cleaning bath 370 having a liquidcleaning material 372. Alternatively, the stint 330 may be cleaned byimmersion and brushing in a conventional cleaning bath or a conventionalspray cleaning process.

FIG. 8H is an eighth step in the third embodiment of the presentinvention illustrating the introduction of the active agent 340 withinthe internal region 331 of the stint 330. Thereafter, the stint 330containing the active agent 340 is applied upon the teeth 322 of thepatient as shown in FIG. 9. The termination 334 of the stint 330 sealswith the gingiva 338 to retain the active agent 340 within the internalregion 331 of the stint 330. The presence of the indentations 346 on theinternal surface 331A of the internal region 331 of the stint 330 aidsin retaining the active agent 340 within the stint 330 and in closeproximity to the teeth 322 of the patient to provide superior results.The non-uniform internal surface 331A due to the indentations or baffles346 within the internal region 331 of the stint 330 retains the activeagent 340 within the internal region 331 of the stint 330.

FIG. 9 is an enlarged sectional view of a portion of the improved stint330 shown in FIG. 8 whereas FIG. 10 is a further enlarged sectional viewof FIG. 9. The indentations 346 on the internal surface 331A provides aplurality of baffles to trap and hold the active agent 340 against thetooth 322 to provide a superior performance relative to the prior art.The plurality of indentations 346 formed on the inside surface 331Aretains the active agent 340 within the stint 330 and impedes thewashing away of the active agent 340 from the stint 330.

The plurality of indentations 346 disposed on a right side 331R of theinternal surface 331A of the stint 330 are uniformly disposed about aright side 222R of the tooth 222 of the patient. Accordingly, the activeagent 340 stays in uniform contact with the right side surface 222R ofthe teeth 322.

As best shown in FIG. 9, the improved stint 310 enables the selectivetreatment of a single tooth or a selected portion or portions of asingle tooth or a plurality of teeth. An indentation 346L disposed on aleft side 331L of the internal surface 331A of the stint 330 ispreferentially enlarged relative to the indentations 346 disposed on theright side 331R of the internal surface 331A of the stint 330.

When only a selected portion 322S of the tooth 322 requires thetreatment by the active agent 340, a selected portion of the internalsurface 331A of the stint 330 is formed with the preferentially enlargedindentation 346L. The preferentially enlarged indentation 346L is formedby an operator to be adjacent the selected portion 322S of the tooth322. The enlarged indentation 346L may be created by directing thenozzle 362 of the abrasive blaster 366. Preferential abrasive blastingby the abrasive blaster 366 will produce a preferential enlargedindentation 346L in the internal surface 331A of the stint 330. Theenlarged indentation 346L will retain a greater amount of the activeagent 340 to apply a faster treatment to the selected portion 322S ofthe tooth 322.

When the active agent is applied to the internal portion 331 of thestint 330, the enlarged indentation 346L is in register with theselected portion 322S of the tooth 322 for preferentially treating theselected portion 322S of the tooth 322.

The apparatus and method of the present invention may be utilized invarious treatments of a tooth or other oral structures including thetreatment for whitening teeth, fluoride treatment, as well as theapplication of antibiotics, antihistamines, topical anesthetics,chemotherapy, steroids, astringents, antiseptics, anti-inflammatory andthe like.

In periodontal procedures such as root planing and deep scaling, thestint can be placed in the mouth of the patient to apply a topicalanesthetic several minutes prior to the procedure thereby reducing thediscomfort or pain to the patient. The improved stint may be used toapply a fluoride treatment for reducing post operative complications,for remineralizing the damaged areas of the root surfaces as well asinsulating the surfaces to prevent sensitivity.

The improved stint of the present invention may be used in antihistamineprocedures to reduce topical inflammation of periodontal structures,fluoride treatment such as the treatment of decalcification, radiationtherapy and rampant caries, acute sensitive and xerostomia.

In one example, the apparatus and method of the present invention hasbeen successfully used in a tooth whitening process. A solution of 11%perhydrol urea in a base solution of glycerine (99.9% water free) with abase stabilizer of 0,015% potassium citrate has been found to beeffective as a tooth whitening agent.

The stint may be formed from a variety of materials such as polymers,copolymers, composites and the like. Stints have been successfullyformed from 0.020" to 0.040" polycarbonate coping material. Thepolycarbonate material has been found to be more comfortable for thepatient than harder material such as acrylics and the like. Furthermore,the resiliency of the polycarbonate material does not produce undesiredorthodontic movement.

The foam retaining material shown in FIGS. 2A-2F may be selected from avariety of materials as should be apparent to those skilled in the art.However, superior results have been achieved using low density foampolyethylene in a thickness range of 1/32" to 3/32". In a similarmanner, the fibrous retaining material shown in FIGS. 3A-3I may beselected from a variety of materials having a thickness of 0.001" to0.005". For example, conventional filters for drip coffee makers havebeen found to be an effective fibrous retaining material. Other suitablematerials include medical grade milioliform filter material.

The apparatus and method of the present invention when applied to atooth whitening process has been found to produce faster results withless discomfort for the patient than the prior art process shown inFIGS. 1A-1F.

The present disclosure includes that contained in the appended claims aswell as that of the foregoing description. Although this invention hasbeen described in its preferred form with a certain degree ofparticularity, it is understood that the present disclosure of thepreferred form has been made only by way of example and that numerouschanges in the details of construction and the combination andarrangement of parts may be resorted to without departing from thespirit and scope of the invention.

What is claimed is:
 1. An improved apparatus for treating a toothembedded in gingiva tissue with an active agent, comprising:a stinthaving an internal region and an external region with the internalregion of said stint defined for overlaying the tooth; said stintcomprising a sheet of plastic material having an internal surface whichis shaped for defining tile tooth surface to be treated in said internalregion of said stint, said internal surface including at least oneinternal side surface disposed for overlaying at least a portion of aside surface of the tooth; one or more indentations formed in saidinternal side surface of said plastic material; and said one or moreindentations dimensioned and disposed for retaining the active agenttherein enabling the active agent to be maintained in contact with atleast a portion of a side surface of the tooth when said stintcontaining the active agent is applied upon the tooth.
 2. The improvedapparatus of claim 1, wherein said stint comprises a molded sheet ofplastic material.
 3. The improved apparatus of claim 1, wherein said oneor more indentations are integrally formed in said internal surface ofsaid plastic material.
 4. The improved apparatus of claim 1, whereinsaid plurality of indentations are preferentially formed into a selectedportion of said internal region of said stint to preferentially treat aselected portion of the tooth adjacent said portion of said one or moreindentations.
 5. In combination with the improved apparatus of claim 1an active agent comprising a bleaching agent comprising a solution of11% perhydrol urea in a base solution of glycerine with a basestabilizer of 0.015% potassium citrate.
 6. An improved apparatus fortreating a plurality of teeth embedded in a gingiva tissue with anactive agent, comprising:a stint having a defined internal region and anexternal region, the internal region overlaying the teeth to be treated;said stint terminating at the juncture of the teeth and the gingiva andforming a seal thereon; and means in the internal region of the stintfor selectively spacing the stint a predetermined selectively variabledistance apart from the surface of the teeth to be treated.
 7. Animproved method of treating a tooth with an active agent comprising ableaching agent of perhydrol urea in a base solution of glycerine,comprising the steps of:making a model of the tooth; molding a stint todefine an internal region for receiving the active agent wherein thestep of molding the stint includes disposing a retaining material atleast partially over the model of the tooth and vacuum forming a sheetof plastic material over the retaining material and the model of thetooth to form a spacing of the internal region of the stint apart fromthe surface of the tooth; trimming the stint to terminate at thejuncture of the tooth and gingiva tissue; introducing an active agentcomprising perhydrol urea in a base Solution of gylcerine into theinternal region; and applying the stint containing the active agent,upon the tooth.
 8. An improved method of treating a tooth with an activeagent, comprising the steps of:making a model of the tooth; positioninga retaining material between the model of the tooth and a stintmaterial; selectively varying the thickness of said retaining materialto selectively vary the spacing between said stint material and thetooth; molding a stint from the stint material over the retainingmaterial to define an internal region and an external region with tileretaining material being adjacent to the internal region to space thestint apart from the tooth when in place; introducing the active agentinto the stint; and applying the stint containing the active agent uponthe tooth.
 9. The method of claim 8, further comprising the step ofproviding at least one baffle in said retaining material.
 10. Animproved method of treating a selected surface portion of teeth with anactive agent, comprising the steps of:making a model of the teeth;positioning a retaining material between at least one selected toothsurface portion of the model of the teeth and a stint material, suchthat the thickness of said retaining material between said model andsaid stint material is non-uniform; molding a stint from the stintmaterial over the retaining material to define an internal region and anexternal region with the retaining material being adjacent to theinternal region to selectively space the stint a predetermined thicknessapart from at least one selected tooth surface portion when in place;introducing the active agent into the stint; and applying the stintcontaining the active agent upon the teeth.
 11. The method of claim 10,further comprising the step of selectively varying the thickness of saidretaining material to selectively vary the spacing between said stintand the tooth.